The squadron's most effective antisubmarine patrols were conducted from 18 July to 2 August 1943, the period in which the unit made nearly all of its attacks on enemy U-boats. After that time the enemy avoided surfacing during daylight and adopted a policy of evasion, but the squadron continued its patrols, often engaging Luftwaffe fighter interceptor aircraft such as the Junkers Ju 88, the Messerschmitt Bf 109 and the Messerschmitt Bf 110) in combat. The Focke-Wulf 200 was also encountered.

The 19th was moved to RAF Dunkeswell in Dorset during early August 1943 and ended operations in October 1943 after aerial antisubmarine missions were turned over to the United States Navy. B-24s reassigned to Navy Patrol Bomber Squadron VPB-103, Fleet Air Wing 7 at Dunkeswell were redesignated PB4Ys.